The present invention relates to a module apparatus of the type used to receive an optoelectronic device package and a circuit board for coupling to the optoelectronic device package. The present invention also relates to a method of assembling the module apparatus.
An optical transceiver module is package comprising a transmission connector for coupling a first optical fibre to an optical transmitter sub-assembly, a reception connector for coupling a second optical fibre to an optical receiver sub-assembly, a transmitter Printed Circuit Board (PCB) coupled to the optical transmitter sub-assembly, and a receiver PCB coupled to the optical receiver sub-assembly. The optical transceiver module is typically manufactured by an optoelectronic equipment manufacturer for a customer, the customer being desirous to couple the optical transceiver module to a custom-built PCB.
Due to the different physical configurations of different optical transceiver designs of various optoelectronic equipment manufacturers, a number of these optoelectronic equipment manufacturers agreed to conform to certain common configuration parameters (known as the small form factor multisource agreement for optical transceivers). In particular, spacings between pins of the transceiver module relating to the optical receiver sub-assembly and a receiver optical reference plane of the optical receiver sub-assembly, and between pins of the transceiver module relating to the optical transmitter sub-assembly and a transmitter optical reference plane of the optical transmitter sub-assembly have been agreed. Consequently, the customer is free to design the custom PCB without the restriction of having to source optical transceiver equipment from a single optoelectronic equipment manufacturer.
The agreed common configuration parameters relating to the optical transceiver module are such that the above-mentioned spacings are 1.33 mm each. Such distances are very small and are very difficult to attain the spacings between the pins and the respective optical reference planes with direct connections between the receiver PCB and the optical receiver sub-assembly and the transmitter PCB and the transmitter sub-assembly.
In order to remove the fixed relationship between the pins of the receiver PCB and the optical receiver sub-assembly and the pins of the transmitter PCB and the optical transmitter sub-assembly, it is known to couple one end of a first flex circuit to the receiver PCB and the other end of the first flex circuit to the optical receiver sub-assembly. Similarly, one end of a second flex circuit is coupled to the transmitter PCB and the other end of the second flex circuit is coupled to the optical transmitter sub-assembly. The use of the first and second flex circuits make configurations of the transmitter PCB, the receiver PCB, the optical transmitter sub-assembly and optical receiver sub-assembly within the optical transceiver module more versatile with respect to other known optical transceiver module designs requiring direct connection between the receiver PCB and the optical receiver sub-assembly and between the transmitter PCB and the optical transmitter sub-assembly.
However, each of the first and second flex circuits require twice as many solder connections than a direct connection. Also, the first and second flex circuits constitute additional components. The above disadvantages impact upon yield, cost and reliability of the optical transceiver module.
According to the present invention, there is provided a module apparatus for coupling to an optical fibre and a circuit board, said apparatus comprising: a circuit board card defining a planar surface and an edge, and a base for location substantially parallel to a circuit board, said base being arranged to receive an optoelectronic sub-assembly and a circuit board card, said optoelectronic sub-assembly including an optoelectronic device; and said optoelectronic sub-assembly coupled to said circuit board card; wherein: said circuit board card comprises a plurality of pins attached to said edge of said circuit board card and extending away from said edge substantially parallel to said surface of said circuit board card, and said base comprises a plurality of recesses or apertures therein permitting passage of said plurality of pins through said base so that said plurality of pins act as a plurality of pins of said module for coupling to said circuit board and enable said circuit board card to be disposed substantially perpendicular to said base.
Preferably, the apparatus further comprises an optical centreline associated with said optoelectronic sub-assembly and a centreline associated with said pins, wherein said optoelectronic sub-assembly is disposed relative to said circuit board card so that a shortest distance between said centreline of said pins and said optical centreline is maintained at a predetermined distance. More preferably, said shortest distance is substantially 1.33 mm.
Preferably, said plurality of recesses or apertures are disposed so as to align said circuit board card relative to said optical sub-assembly when said plurality of pins pass through said apertures or recesses.
In a preferred embodiment of the invention, an optoelectronic module apparatus is provided for coupling to an optical fibre and a circuit board, said apparatus comprising: an optoelectronic sub-assembly having a plurality of terminals, said optoelectronic sub-assembly including an optoelectronic device, a circuit board card defining a substantially rectangular planar surface having a longitudinal edge, and a skeleton comprising a base for location substantially parallel to a circuit board, said skeleton being arranged to receive said optoelectronic sub-assembly and said circuit board card, wherein said plurality of terminals of said optoelectronic sub-assembly are directly coupled to said circuit board card; said circuit board card comprises a plurality of pins attached along said longitudinal edge of said circuit board card and extending away from said longitudinal edge substantially parallel to said surface of said circuit board card, and said base comprises a plurality of aligned recesses therein permitting said plurality of pins to pass through said floor so that said plurality of pins act as a plurality of pins of said optoelectronic module for coupling said optoelectronic module to said circuit board, and to enable said circuit board card to be disposed substantially perpendicular to said base of said skeleton.
According to the present invention, there is also provided a method of assembling a module apparatus comprising a circuit board card defining a planar surface and an edge, and a base for location substantially parallel to a circuit board, said base being arranged to receive an optoelectronic sub-assembly and a circuit board card, said optoelectronic sub-assembly including an optoelectronic device, and said optoelectronic sub-assembly being coupled to said circuit board card, said circuit board card comprising a plurality of pins attached to said edge of said circuit board card and extending away from said edge substantially parallel to said surface of said circuit board card, and said base comprises a plurality of recesses or apertures therein, the method comprising the steps of: installing said optoelectronic sub-assembly onto said base; installing said circuit board card by passing said plurality of pins into said plurality of recesses or apertures so that said plurality of pins are disposed substantially perpendicular to said base; coupling said optoelectronic sub-assembly to said circuit board card.
Preferably, the method further comprises the step of: directly coupling said optoelectronic sub-assembly to said circuit board card by soldering said optoelectronic sub-assembly to said circuit board card.
The method may further comprise the step of: attaching said plurality of pins to the edge of said circuit board card using a lead frame.
Preferably, said plurality of pins is attached to said circuit board card using a lead frame.
In another preferred embodiment of the invention, there is provided a method of assembling an optoelectronic module apparatus comprising an optoelectronic sub-assembly having a plurality of terminals, said optoelectronic sub-assembly including an optoelectronic device, a circuit board card defining a substantially rectangular planar surface and a longitudinal edge, and a skeleton comprising a base for location substantially parallel to a circuit board, said skeleton being arranged to receive said optoelectronic sub-assembly and said circuit board card, said circuit board card comprising a plurality of pins attached along said longitudinal edge of said circuit board card and extending away from said longitudinal edge substantially parallel to said surface of said circuit board card, and said base comprises a plurality of aligned recesses therein, the method comprising the steps of: coupling said optoelectronic sub-assembly to said skeleton; placing said circuit board card onto said base so that said plurality of pins pass into said plurality of recesses; coupling said plurality of terminals of said optoelectronic sub-assembly to said circuit board card.
It is thus possible to provide an optical transceiver module that has fewer parts and hence is more reliable and economical (in terms of components) than prior optical transceiver modules. The method of assembling the optical module also results in an optical module that needs to be subject to fewer manufacturing steps and so is quicker and cheaper to manufacture.